CALCULATION OF DIELECTRIC FUNCTION FOR A DEGENERATE ELECTRON GAS WITH INTERACTION .2. FREQUENCY DEPENDENCE

Starting from an expression for the dielectric function earlier derived, we calculate explicitly the ω dependence of the G(k,ω) function which describes correlation and exchange effects. The full frequency dependence of this function is found to be rather significant; in particular it improves the accuracy with which the f sum rule is satisfied, which confirms the goodness of the approximations involved in the calculation of the dielectric function. © 1971 The American Physical Society